Nucleated cells are highly sensitive to hypoxia and even short periods of ischemia in multi-cellular organisms can have dramatic effects on cellular morphology, gene transcription, and enzymatic processes. Mitochondria, as the major site of oxygen metabolism, are particularly sensitive to changes in oxygen levels and during hypoxia release reactive oxygen species that chemically modify intracellular constituents such as lipids and proteins. Clinically these effects manifest as an inflammatory response in the patient. Despite intensive investigations of cellular responses to hypoxia little is known regarding the initiation of acute inflammation.
Acute inflammatory responses can result from a wide range of diseases and naturally occurring events such as stroke and myocardial infarction. Common medical procedures can also lead to localized and systemic inflammation. Left untreated inflammation can result in significant tissue loss and may ultimately lead to multi-system failure and death. Interfering with the inflammatory response after injury may be one method to reduce tissue loss.
Inflammatory diseases and acute inflammatory responses resulting from tissue injury, however, cannot be explained by cellular events alone. Accumulating evidence supports a major role for the serum innate response or complement system in inflammation. Studies to date have looked at tissue injury resulting from ischemia and reperfusion as one type of inflammatory disorder that is complement dependent. For example, in the rat myocardial model of reperfusion injury, pretreatment of the rats with the soluble form of the complement type 1 receptor dramatically reduced injury. Understanding how complement activation contributes to an inflammatory response is an area of active investigation.
Inflammatory diseases or disorders are potentially life-threatening, costly, and affect a large number of people every year. Thus, effective treatments of inflammatory diseases or disorders are needed.